Add Gemfile to support jekyll 4.0.0 (aweekj#16)

* Add Gemfile to support jekyll 4.0.0

* Remove Gemfile from exclued list

.gitignore

@@ -2,9 +2,8 @@ _site
 .DS_Store
 .jekyll
 .jekyll-metadata
+.jekyll-cache
 .bundle
 .sass-cache
-Gemfile
-Gemfile.lock
 node_modules
 package.json

Gemfile

@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+source "https://rubygems.org"
+
+gem "jekyll-sitemap"
+gem "jekyll-feed"
+gem "jekyll-paginate"

Gemfile.lock

@@ -0,0 +1,74 @@
+GEM
+  remote: https://rubygems.org/
+  specs:
+    addressable (2.7.0)
+      public_suffix (>= 2.0.2, < 5.0)
+    colorator (1.1.0)
+    concurrent-ruby (1.1.5)
+    em-websocket (0.5.1)
+      eventmachine (>= 0.12.9)
+      http_parser.rb (~> 0.6.0)
+    eventmachine (1.2.7)
+    ffi (1.11.1)
+    forwardable-extended (2.6.0)
+    http_parser.rb (0.6.0)
+    i18n (1.6.0)
+      concurrent-ruby (~> 1.0)
+    jekyll (4.0.0)
+      addressable (~> 2.4)
+      colorator (~> 1.0)
+      em-websocket (~> 0.5)
+      i18n (>= 0.9.5, < 2)
+      jekyll-sass-converter (~> 2.0)
+      jekyll-watch (~> 2.0)
+      kramdown (~> 2.1)
+      kramdown-parser-gfm (~> 1.0)
+      liquid (~> 4.0)
+      mercenary (~> 0.3.3)
+      pathutil (~> 0.9)
+      rouge (~> 3.0)
+      safe_yaml (~> 1.0)
+      terminal-table (~> 1.8)
+    jekyll-feed (0.12.1)
+      jekyll (>= 3.7, < 5.0)
+    jekyll-paginate (1.1.0)
+    jekyll-sass-converter (2.0.0)
+      sassc (> 2.0.1, < 3.0)
+    jekyll-sitemap (1.3.1)
+      jekyll (>= 3.7, < 5.0)
+    jekyll-watch (2.2.1)
+      listen (~> 3.0)
+    kramdown (2.1.0)
+    kramdown-parser-gfm (1.1.0)
+      kramdown (~> 2.0)
+    liquid (4.0.3)
+    listen (3.1.5)
+      rb-fsevent (~> 0.9, >= 0.9.4)
+      rb-inotify (~> 0.9, >= 0.9.7)
+      ruby_dep (~> 1.2)
+    mercenary (0.3.6)
+    pathutil (0.16.2)
+      forwardable-extended (~> 2.6)
+    public_suffix (4.0.1)
+    rb-fsevent (0.10.3)
+    rb-inotify (0.10.0)
+      ffi (~> 1.0)
+    rouge (3.11.0)
+    ruby_dep (1.5.0)
+    safe_yaml (1.0.5)
+    sassc (2.2.1)
+      ffi (~> 1.9)
+    terminal-table (1.8.0)
+      unicode-display_width (~> 1.1, >= 1.1.1)
+    unicode-display_width (1.6.0)
+
+PLATFORMS
+  ruby
+
+DEPENDENCIES
+  jekyll-feed
+  jekyll-paginate
+  jekyll-sitemap
+
+BUNDLED WITH
+   1.17.2

_config.yml

@@ -104,8 +104,6 @@ plugins:
 
 # Exclude these files from your production _site
 exclude:
-  - Gemfile
-  - Gemfile.lock
   - LICENSE
   - README.md
   - CNAME